The present invention relates to a hydraulic control apparatus for an automatic transmissions and a hybrid drive system that is provided with the same.
There exists an automatic transmission that is mounted in a vehicle such as an automobile, for example. In the automatic transmission, electronic control controls the engagement pressure that is carried out in order to reduce the engagement shock (shifting shock) of the clutches and brakes during acceleration and clamp shifting. Conventionally, a common hydraulic control apparatus that controls the engagement pressure in this manner is one in which a line pressure or a range pressure is regulated by using a linear solenoid valve and a control valve, and supplied to the hydraulic servo of each of the clutches and brakes (Japanese Patent Application Publication No. JP-A-2001-343067, for example).